Dark Side of the Moon
by ofhellhoundsandhunters
Summary: It's been nearly two months and the boys are finally closing in on Abaddon, just in time too since the Mark of Cain seems to be consuming Dean both physically and mentally. Meanwhile Cas' stolen grace is quickly wearing off and he's turning human once more. Of course nothing ever goes as planned; as Dean goes to kill Abaddon, he is quickly caught off guard by what he finds.


A/N: written for Quick Fic Friday at quickficfriday (you should check out her blog because she's awesome)

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The blood pounding through Dean's head was only dulled by the ringing in his ears. With each step he took, the mark burned stronger. It urged him to go further when he knew that he should be doing the exact opposite.

He shouldn't have left Sam behind, he shouldn't have come here alone. They had tracked Abaddon down to a small town in Illinois, the plan was to go looking for her in the morning but Dean couldn't wait. As he walks through the abandoned halls he rehearses what he'll say to an angry Sam when he gets back to the motel – _if you had felt the pull, you wouldn't have resisted either_. He would be upset but eventually understand, he always did, Sam was good that way.

Castiel on the other hand would be furious. As if the mark itself wasn't bad enough, Cas hadn't taken too kindly to the change in Dean's personality. A change that Dean himself insisted was nonexistent – which was another problem entirely. A few days ago he had stopped answering their calls. The brothers agreed it was because he was busy assembling his army for a fight against Metatron, but the Winchesters knew better.

He was angry at Dean. Hurt and confused when he had snapped at him last week for something so diminutive, that Dean could barely remember what it was. The conversation plays once through his head.

"_So your stolen grace is wearing out?" _

"_Yes."_

"_You're becoming human again?" _

_There was a sigh and then a mumbled, "Yes." _

"_So even when we find Abaddon, you can't even help us get to her. You're useless in this entire fight." There was silence from everyone in the room. Castiel and Sam looked towards one another for guidance._

"_Dude, what's wrong with you?" Sam finally asked breaking the silence._

"_Nothing." Dean growled. "I just don't see the point of having a bum angel hanging on our shoulders when he could be off doing something useful instead of getting in my way."_

"_This isn't you." When he finally spoke Cas' voice was firm, it reminded Dean of the first time they had met all those years ago. "I don't even know _what_ you are, Dean." That was the last thing he had said before storming out._

Sam and Cas were both overeating, Dean was fine and he knew he could take Abaddon down by himself. Hell, he had to. Without the mark no one could really help him at this point, everyone would just be in the way.

He glances towards the glowing mark. It had changed him but that wasn't necessarily a bad thing. The truth was, Dean had never been this strong before, nor had he ever been this driven or focused.

The blade rests comfortably in his right hand, as if it had always belonged there. There's a sound of rats scouring on the wooden floor but he doesn't even blink, his attention is focused on one thing. Killing Abaddon and ending all of this. Once she was out of the picture he only had to worry about Metatron and he was confident Castiel had a strong army ready to help with that.

It doesn't take long to find her. The church wasn't large and the mark made an almost perfect tracking device. The throbbing intensified with every step he took in the right direction. He silently approaches the hooded figure facing away from him. For a momentary second, he muses how easy this had all been, but he quickly brushes it off as the mark's doing and raises the blade to strike.

"Hello, Dean." He freezes. His arm ached more than ever, begging him to thrust the blade into the Knight's back but something had made him stop – the familiarity of that voice. He can feel the blood drain from his face as he watches the figure turn around and lower their hood.

"Cas?" It was a hopeful question, one that he already knew the answer to.

"Why does it always have to be churches?" His voice contained its usual roughness but there was something different. He sighs and turns to face Dean. "I suppose it's more poetic this way."

"Who are you? Because you sure as hell ain't Cas." Dean can barely hear himself speak over the buzzing in his head. The mark burned brighter, illuminating the entire room, Dean had to suppress the urge to react as the pain continued to intensify. It was screaming, pleading with him to attack but he couldn't move.

"You're smart... maybe not as clever as your Grandfather or little Sammy...but go ahead, take a shot, Winchester?" The condescending tone only infuriates Dean further and it takes all the self control he can muster not to attack. Dean watches as he tilts his head to the side and smiles. A deep laugh cracks the air in half. He knew that the moment he said the name out loud, it made all of this real. This wasn't how it was supposed to be, it was all wrong.

"Abaddon." The name cuts like ice through the air, it sends a sharp surge down through his arm. A simple confirmation that he's right.

"Bingo."The blade burned in his hand as Dean watched the blue eyes he had so often found comfort in change to a startling black.

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A/N: Please let me know what you think. Thank you for reading :)


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